hugetlb: fix resv_map leak in error path

diff -puN mm/hugetlb.c~hugetlb-fix-leak mm/hugetlb.c
@@ -2157,6 +2157,15 @@ static void hugetlb_vm_op_open(struct vm
 		kref_get(&reservations->refs);
 }
 
+static void resv_map_put(struct vm_area_struct *vma)
+{
+	struct resv_map *reservations = vma_resv_map(vma);
+
+	if (!reservations)
+		return;
+	kref_put(&reservations->refs, resv_map_release);
+}
+
 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
 {
 	struct hstate *h = hstate_vma(vma);

@@ -2173,7 +2182,7 @@ static void hugetlb_vm_op_close(struct v
 		reserve = (end - start) -
 			region_count(&reservations->regions, start, end);
 
-		kref_put(&reservations->refs, resv_map_release);
+		resv_map_put(vma);
 
 		if (reserve) {
 			hugetlb_acct_memory(h, -reserve);

@@ -2990,12 +2999,16 @@ int hugetlb_reserve_pages(struct inode *
 		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
 	}
 
-	if (chg < 0)
-		return chg;
+	if (chg < 0) {
+		ret = chg;
+		goto out_err;
+	}
 
 	/* There must be enough pages in the subpool for the mapping */
-	if (hugepage_subpool_get_pages(spool, chg))
-		return -ENOSPC;
+	if (hugepage_subpool_get_pages(spool, chg)) {
+		ret = -ENOSPC;
+		goto out_err;
+	}
 
 	/*
 	 * Check enough hugepages are available for the reservation.

@@ -3004,7 +3017,7 @@ int hugetlb_reserve_pages(struct inode *
 	ret = hugetlb_acct_memory(h, chg);
 	if (ret < 0) {
 		hugepage_subpool_put_pages(spool, chg);
-		return ret;
+		goto out_err;
 	}
 
 	/*

@@ -3021,6 +3034,9 @@ int hugetlb_reserve_pages(struct inode *
 	if (!vma || vma->vm_flags & VM_MAYSHARE)
 		region_add(&inode->i_mapping->private_list, from, to);
 	return 0;
+out_err:
+	resv_map_put(vma);
+	return ret;
 }
 
 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)

diff -puN include/linux/mmzone.h~sparsemem-fix-boot-when-SECTIONS_PER_ROOT-is-not-power_of_2 include/linux/mmzone.h
@@ -1018,6 +1018,12 @@ struct mem_section {
 	struct page_cgroup *page_cgroup;
 	unsigned long pad;
 #endif
+	/*
+	 * WARNING: Do not put any fields here that could cause
+	 * this structure to become a non-power-of-2 size.
+	 * Operations like pfn_to_page() will end up doing
+	 * division in hot paths for CONFIG_SPARSEMEM_EXTREME.
+	 */
 };
 
 #ifdef CONFIG_SPARSEMEM_EXTREME

@@ -1028,7 +1034,6 @@ struct mem_section {
 
 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
 #define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
-#define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
 
 #ifdef CONFIG_SPARSEMEM_EXTREME
 extern struct mem_section *mem_section[NR_SECTION_ROOTS];

@@ -1040,7 +1045,7 @@ static inline struct mem_section *__nr_t
 {
 	if (!mem_section[SECTION_NR_TO_ROOT(nr)])
 		return NULL;
-	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
+	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr % SECTIONS_PER_ROOT];
 }
 extern int __section_nr(struct mem_section* ms);
 extern unsigned long usemap_size(void);

diff -puN mm/sparse.c~sparsemem-fix-boot-when-SECTIONS_PER_ROOT-is-not-power_of_2 mm/sparse.c
@@ -63,6 +63,11 @@ static struct mem_section noinline __ini
 	unsigned long array_size = SECTIONS_PER_ROOT *
 				   sizeof(struct mem_section);
 
+	/*
+	 * See note in 'struct mem_section' definition
+	 */
+	WARN_ON_ONCE(!is_power_of_2(sizeof(struct mem_section)));
+
 	if (slab_is_available()) {
 		if (node_state(nid, N_HIGH_MEMORY))
 			section = kmalloc_node(array_size, GFP_KERNEL, nid);